Large-Scale Fabrication of Submicrometer-Gate-Length MOSFETs With a Trilayer PtSe2 Channel Grown by Molecular Beam Epitaxy

This article is the first report of MOSFETs fabricated on PtSe2 grown by molecular beam epitaxy. Both material synthesis and device fabrication are done below 450 °C—the thermal budget of CMOS back-end-of-line processes. The MOSFETs are batch-fabricated by a CMOS-compatible process on 200-mm-diameter Si substrates prepared by a state-of-the-art BiCMOS foundry. With three monolayers of PtSe2, an n-type MOSFET exhibits a current ON/OFF ratio of 43 at room temperature, which increases to 1600 at 80 K. These results are among the best of transistors based on synthesized PtSe2. Despite the thin PtSe2 layer, doping by contact bias lowers the contact resistance significantly and boosts the current capacity and the ON/OFF ratio. Temperature-dependent current-voltage characteristics imply a bandgap of approximately 0.2 eV, which confirms that the semiconductor-semimetal transition of PtSe2 is not as abrupt as originally predicted. Better MOSFET performance can be expected by growing even thinner PtSe2 uniformly and by thickening the PtSe2 in the contact regions.